rini:speed_log_notes
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rini:speed_log_notes [2009/04/17 05:04] ben |
rini:speed_log_notes [2011/04/11 09:00] ben [Notes dumping place for possible Arduino speed-log] |
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| ====== Notes dumping place for possible Arduino speed-log ====== | ====== Notes dumping place for possible Arduino speed-log ====== | ||
| - | == ALL DEPENDS on proven functionality of the speed transducer- first things first, remove transducer and test... == | + | |
| + | <del>ALL DEPENDS on proven functionality of the speed transducer- first things first, remove transducer and test...</del> | ||
| + | |||
| + | **Update 04/11/2011**: The speed log transducer was removed from the boat, drilled out, and a new reed switch wired and seated, and the whole unit was then re-potted and placed back in the hull. | ||
| + | |||
| + | It seems the [[http://www.pjrc.com/teensy/|"Teensy"]] may be the best board for the jobs. The board retains a USB connector, so will be easy to update/troubleshoot. | ||
| + | |||
| + | Display Unit: the main unit should have two or three RS232 NMEA0183 inputs. First function button should scroll through those inputs, a long hold should change the number of inputs on the display (i.e. one input, two inputs side by side, two inputs vertical, three inputs, etc.). Ability to set input type (depth, speed, GPS location, GPS Speed, others?). | ||
| + | |||
| + | Speed sender: leads to the reed switch in the sender are the simplest to extend, so a teensy should be enclosed along with power toggle, and calibration momentary switches. Output of the teensy should be NMEA0183 serial over RS232. | ||
| + | |||
| + | Depth unit: should be an "intelliducer" type, which outputs NMEA0183 sentences. | ||
| + | |||
| + | Possible displays: | ||
| + | |||
| + | * Some of the graphic displays do not have fonts, making them much more complicated. | ||
| + | |||
| + | |||
| + | [[http://www.pjrc.com/tech/8051/board5/lcd_128x64.html|Graphic & Non-serial]] | ||
| + | |||
| + | [[http://store.seetron.com/bpp420vy-4x20-serial-lcdinverse-modeyellow-led-bac420420.html|Light on dark 4-line Serial with Bell (expensive at $60)]] | ||
| + | |||
| + | [[http://www.sparkfun.com/products/9560|Large Graphic, Serial, E-ink type operation (expensive at $80)]] | ||
| + | |||
| + | [[http://store.seetron.com/serial-oleds.html|OLED two-line with Large Fonts (also expensive at $50)]] | ||
| + | |||
| + | Someone else's Arduino based speed log: [[http://www.holdentechnology.com/component/content/article/36-sailing-projects/58-speedo]] | ||
| + | |||
| + | Older thoughts: | ||
| * Planned platform is Arduino NANO with Serial LCD. | * Planned platform is Arduino NANO with Serial LCD. | ||
| - | * Arduino Mini is cheaper by %50 apparently... | + | * Arduino Mini is cheaper by %50 apparently... but requires additional USB connection- PICAXE USB cable may be suitable. |
| * Important is display type- black on white is best for sunlight conditions. Backlight also required. Maybe white on blue would work well in sunlight? | * Important is display type- black on white is best for sunlight conditions. Backlight also required. Maybe white on blue would work well in sunlight? | ||
| * Important is character support- LARGE NUMBERS are necessary. | * Important is character support- LARGE NUMBERS are necessary. | ||
| Line 12: | Line 40: | ||
| * For now it seems that traveling 1 mile and counting the number of transducer clicks will provide an adequate average result | * For now it seems that traveling 1 mile and counting the number of transducer clicks will provide an adequate average result | ||
| * Once the number of clicks for 1 n. mile is found, math is Distance in n. mile divided by time in hours = Speed in knots, choose a very small unit of time to count clicks for to allow fast updates of speed calculation (2s?) | * Once the number of clicks for 1 n. mile is found, math is Distance in n. mile divided by time in hours = Speed in knots, choose a very small unit of time to count clicks for to allow fast updates of speed calculation (2s?) | ||
| - | <tab><code> | ||
| - | Best I can get this described in ASCII: | ||
| + | Best I can get this described in ASCII: | ||
| + | <tab><blockquote> | ||
| D = distance in nautical miles | D = distance in nautical miles | ||
| + | |||
| T = time in hours | T = time in hours | ||
| + | |||
| S = speed in knots | S = speed in knots | ||
| Line 22: | Line 52: | ||
| X = Number of clicks counted while traveling a calibration mile | X = Number of clicks counted while traveling a calibration mile | ||
| + | |||
| Y = Number of clicks counted in a single sample period | Y = Number of clicks counted in a single sample period | ||
| + | |||
| Z = Sample period in Seconds | Z = Sample period in Seconds | ||
| D = Y/X * 1 n.m. | D = Y/X * 1 n.m. | ||
| + | |||
| T = Z/3600 | T = Z/3600 | ||
| - | So: (Z/X * 1 n.m.) / (Z/3600) = Speed in knots for the sample period Z | + | So: (Y/X * 1 n.m.) / (Z/3600) = Speed in knots for the sample period Z |
| + | |||
| + | E.G. If we calibrate 1 n.m. at 2500 clicks (X=2500) and our sample/update period is 2 seconds (Z=2), and over that period we count 10 clicks (Y=10), then calculated speed would be (10/2500)/(2/3600) = S = 0.004 / 0.0006 = 6.67 knots. | ||
| + | |||
| + | Hopefully we get faster turn rates that 5 rotations per second, otherwise it won't be very precise. | ||
| + | </blockquote> | ||
| - | E.G. If we calibrate 1 n.m. at 2500 clicks (X=2500) and our sample/update period is 2 seconds (Z=2), and over that period we count 30 clicks (Y=30), then calculated speed would be (30/2500)/(2/3600) = S = 0.012 / 0.0011 = 1.0909 knots. | ||
| - | </code> | ||
rini/speed_log_notes.txt · Last modified: 2011/04/11 09:20 by ben
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